OMG, they are both so adorable! :D

So Hard I really like both!

I do like both, but I love Lum's personality more. She' sweeter and even though she had tried a few tricks with Ataru. I feel the big difference between Lum and Shampoo's method was Lum was trying to get Ataru to express what he really felt for her and Shampoo tried to use potions (red thread ect,) that would FORCE Ranma to fall in love with her.
Lum seems to have a little more pure intentions and she's more compassionate toward others, even her enimies sometimes. ( Kinda like AKane.) So even though I really love Shampoo because she adds a lot of fun to Ranma 1/2, and I think its funny how she teases Akane sometimes.( I think they were the best rivals because they were the most fun to watch.)

Between the two of them my vote still goes to Lum.